In the forest industry, the solid volume, not the weight, of the timber is used as a measure for determining the price of delivered timber, for example when logs are delivered to sawmills The measuring of the solid volume of such logs which are usually transported to the sawmill by vehicles on wheels, is, in actual practice, carried out by experienced tallymen who, with the aid of mechanical measuring tools and, possibly, arithmetical tables, estimate the solid biomass content of the load received at the sawmill. This estimate is, however, often rather uncertain and may differ by as much as 10-15% from the actual value. From the economic point of view, this is, of course, unsatisfactory to both suppliers and buyers, as the value of each load of timber may run to considerable amounts of money.